AUXILIARY ENERGY CIRCUIT FOR BATTERY-POWERED POWER TOOL

A system supplies supplemental power to a power tool. The system includes a motor coupled to an output driver, a trigger for user control of power tool operation, a sensor configured to measure an operation characteristic, a battery pack coupled to the motor, and an auxiliary energy supply. A motor controller receives a control signal from the trigger and drives the motor utilizing energy from the battery pack in response to the control signal. The motor controller also receives information from the sensor and provides additional energy to the motor from the auxiliary energy supply depending on the information from the sensor (e.g., motor speed, motor rotational position, motor current, or trigger pull percentage). The controller may connect the auxiliary energy supply in series with the battery pack to supply the supplemental power. A battery charger or energy recapture may be utilized to charge the auxiliary energy supply.